Recently, advances in packaging techniques have led to a substrate for mounting electronic components using ceramics rather than a substrate made from a member of the resin families. Generally, when a high frequency circuit including a UHF tuner, or the like is formed on a printed substrate, a shielding plate is erected (partition plate) to prevent interference and disturbance between individual circuit blocks. In this case, in the prior art, a plurality of legs are formed integrally with the shielding plate, and on the other hand, holes are formed in the printed substrate. The legs are inserted into the holes and soldered to a grounding conductor film on the back side of the printed substrate.
This technique will be described in detail with reference to FIGS. 1A and 1B. In FIGS. 1A and 1B, numeral 1 designates a substrate, 2 a grounding conductor film formed on the back side of the substrate 1, 3 a shielding plate, and 4 designates solder for connecting legs 3a of the shielding plate 3 to the grounding conductor film 2. Further, FIG. 1A is a cross section as viewed from the front side of the shielding plate, and FIG. 1B is a cross section as viewed from the side thereof.
Here, the substrate 1 is provided with rectangular holes for inserting therein the legs 3a of the shielding plate 3, and as shown in FIGS. 1A and 1B, the grounding conductor film 2 and the legs 3a are soldered to each other by passing the substrate 1 through a solder dipping vessel in a condition in which the legs 3a are inserted into the substrate 1.
However, in the arrangement mentioned above, it is necessary to form a multiplicity of rectangular holes in the substrate 1 for shielding therein the legs 3a of the shielding plate 3, and in particular, when a ceramic substrate is used as the substrate 1, a crack is apt to be caused in the substrate 1 from a portion of the corner of the rectangular hole due to a mechanical shock or a heat shock at the time of solder dipping. For example, as the rectangular hole, a hole of 1.5 mm+6 mm may be bored.